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Caption

Kidney. Computer artwork of a longitudinal section through a human kidney. The kidneys filter waste products from the blood, which enters the organ through the renal artery (red) and leaves in the renal vein (blue). The kidney is surrounded by a fibrous capsule (not seen), inside which is the cortex (dark red). Inside the cortex is the medulla (pink/red), where nephrons are located for filtering urine into the renal pelvis (beige). The renal pelvis drains into the ureter, which passes urine to the urinary bladder (not seen), where it is stored.